Significance of protein
Cats are strict carnivores whose typical diets are high in protein, moderate in fats and low in carbohydrates. They should also have all the essential vitamins, minerals, and amino acids, as well as taurine.
There are many protein functions in cats that include being a source of amino acids, which are tissue’s building blocks, form part of antibodies, hormones, and enzymes. Also, they help in maintaining proper pH as well as being the primary energy source together with fats.
AAFCO recommends that crude protein in cat food be at least 30.0% for growth and reproduction, while for adult maintenance, it should be at least 26.0%.
Too little will result in excessive weight loss and negative nitrogen balance and possibly death. You don’t have a skinny, malnourished kitty.
Finally, these pets need highly digestible, high-quality animal source proteins, and not the ones sourced from plants.
At a glance: Top 4 best low protein foods
|Best overall||Hill’s® Prescription Diet® k/d® Chicken Vegetable||4.8||Check Price|
|Runner’s Up||Royal Canin Renal Support E Loaf in Sauce Canned Cat Food||4.6||Check Price|
|Best Dry||Hill’s® Prescription Diet® k/d® Feline with Chicken||4.7||Check Price|
|Best Budget||Royal Canin Renal Support A Dry Cat Food||4.4||Check Price|
Why low protein cat food
Why in perfect health, felines don’t require restricted protein foods. However, the following conditions may be a reason:
1. Chronic kidney disease (CKD)
CKD results in a decline in the functioning of a cat’s kidney, meaning they won’t be able to excrete waste products via urine and concentrating urine effectively. Therefore, they end up suffering from uremia or blood urea nitrogen (BUN), thirst, reduced appetite, and so on.
Research has shown going for best renal diets will help manage CKD. These diets should help reduce or prevent uremia (high level of nitrogenous wastes and urea in blood or blood urea nitrogen), minimize electrolyte (fluid) imbalance, maintain blood pressure and provide all required nutrients.
Furthermore, the diet should also deal with systemic pH derangement and maintain stable weight as well as make them feel better by reducing the progression of CKD and symptoms.
Therefore, CKD diets should be:
a). Lower in protein
Ideal diets should have a lower amount of protein than regular foods, i.e., have 28-35% to reduce uremic products (urea and other nitrogenous wastes) that the kidney has to remove. However, it should not be too low to avoid mass body wasting.
Furthermore, it should be highly digestible and bioavailable to reduce waste products that the kidney remove
The Cornell University of Veterinary Medicine, VCA Hospitals, the Cummings Veterinary Medical Center at Tufts University, and many other sources support renal diets as vital in reducing CKD progression. Their benefits are due to reduced uremic waste products produced during protein catabolism, which will need to be eliminated by the kidney whose efficiency has already declined.
However, not all experts agree on this with some emphasis on the need for high quality, high digestible proteins instead.
For instance, some experts note that the issue should be quality and not quantity. i.e., they claim that there should be a shift to high-quality protein citing reduced palatability (cats not preferring diets such diets). Also, they mention the possibility of muscle loss through catabolism to compensate for the low protein intake. However, the evidence to support this is lacking.
b). Low in phosphorus
Phosphorus in cats helps in the formation of bones, cell membranes, genetic material (DNA and RNA), and works as an enzyme cofactor, among other functions. AAFCO recommends 1.0% and 0.4% on a dry matter basis for growth and adult maintenance, respectively.
Renal diets should have reduced phosphorus, i.e., 0.3-0.6% since high amounts will load the kidney as they try to excrete excess amount and cause hyperphosphatemia. The market has many excellent quality low phosphorus cat foods.
Also, it will high phosphorus accelerate and worsen CKD progress while reducing it will minimize secondary renal hyperparathyroidism.
c). Low in sodium
Sodium functions in cats include maintaining fluid balance, blood pressure, pH balance, and electrolyte balance. AAFCO recommends 0.3 and 0.08% for growth and adult maintenance, respectively. Too little will cause hyponatremia, while too much will cause hypernatremia.
Felines with CKD need low sodium diets to help helps retain normal blood pressure. High blood pressure will force kidneys to work harder. Also, sodium or salt will cause more urination, lead to a depletion in water that is vital for kidney function as well as an electrolyte imbalance.
d). Higher in fatty acids, vitamin B, antioxidants
Essential fatty acids will help reduce inflammatory compounds (neutralize them), while antioxidants will prevent oxidative damage that will worsen CKD.
On vitamin B, since they produce dilute urine, it may be hard for them to maintain a healthy level of water-soluble vitamin, such as vitamin B. Hence they should be added.
2. Liver Disease
The liver helps in the production of proteins that their blood needs including in clotting, food absorption, processing drugs, ammonia, and other metabolites, among many different critical roles.
When cats suffer from liver disease, their liver efficiency converts ammonia, a metabolite of proteins to urea, and other toxic substances declines.
Therefore, a buildup occurs in the blood leading to several conditions, including hepatic encephalopathy. Reducing protein and going for high quality, highly digestible sources will minimize the ammonia buildup in the blood.
3. Older cats don’t need lower protein
Healthy older cats need more proteins and not less. It should be highly digestible, tasty, bioavailable, and palatable since oral problems are common. Higher protein will help reduce the chances of muscle wasting and sarcopenia.
However, since they are more predisposed to chronic renal failure, your vet may recommend lower protein foods. Plus, being a primary source of energy, older cats are not as active as younger ones.
Choosing best low protein cat foods
Selecting the best low protein feline diets understanding how to choose feline diets that include things such as looking at guaranteed analysis and ingredient list to know the sources of protein. Some things to consider include:
1. Nutritionally complete and balanced
Being a therapeutic diet doesn’t mean that the food can have lesser nutrients than as recommended by AAFCO for that specific life stage. You don’t want your kitty to end up skinny and malnourished.
2. High quality and digestible protein source
Settle for foods with highly digestible and bioavailable protein sources. Bioavailability will influence the percentage that they can utilize while these pets excrete the remainder.
Some highly digestible protein sources include poultry, lamb, possum, salmon, and rabbit, among others.
Avoid foods with chicken or meat meals or those with low bioavailability. Poorly digestible proteins yield even higher ammonia and other harmful by-products.
Finally, ensure the amount of protein supports their health and wellbeing. Otherwise, expect muscle wasting.
3. Buy tasty, palatable and highly calorific foods
Felines with CKD tend to have poor appetites. Therefore, foods need to be tasty, palatable, and very enticing. Also, they should have a higher concentration of nutrients and calories so that a small amount eaten is enough to sustain your kitty.
On palatability, most commercial renal diets score well since manufacturers understand that these cats have a poor appetite. You can also add tuna juice, water, chicken broths low in sodium, etc., to encourage eating.
Reduced food intake may cause weakness, lethargy, depression, among other detrimental effects.
3. Choose wet diets unless your cat drinks a lot of water
Cats with CKD cannot excrete toxins. Additionally, they cannot concentrate urine. Therefore, their body stimulates thirst. More water consumption will help in toxin flushing in harmful toxins.
Go for wet foods, and if your kitty likes drinking water, ensure you have a water fountain.
4. Compare prices
Usually, being prescribed diets, expect them to cost slightly more. However, different brands have different prices. Compare them and choose ones that are cheaper yet of good quality.
5. Other consideration
Also, look at preference (what does your cat likes), ask for vet recommendation, and look at the guaranteed analysis, etcetera. Note that while protein goes down, look at what goes high. Avoid those high in carbs.
Best low protein cat foods – wet and dry reviews
Most of the low protein cat foods are actually prescription or veterinary diets for kidney function (for kitties with CKD). Don’t confuse these diets with those for urinary health as the latter doesn’t have to be low in proteins.
1. Hill’s® Prescription Diet® k/d® Feline wet cat food (canned)
Hill’s® Prescription Diet® k/d® Feline is a complete and balanced canned feline diet developed by veterinarians and nutritionists to promote healthy kidney functioning while preventing body mass wasting.
Feeding tests following AAFCO protocol have shown it improves not only longevity but also the quality of a cat with kidney issues.
- Specially developed veterinarians and nutritionists to support and boost a healthy kidney while retaining and building lean muscle.
- Besides the kidneys, it also promotes heart health.
- It has restricted sodium and phosphorus at 0.24 and 0.64 on a dry matter basis, respectively.
- It is high in essential amino acids that form the building blocks of various body tissues, including muscles.
- Has added Omega-3 fatty acids and L-Carnitine
- Its S+OXSHIELDTM formulation helps reduce the risk of struvite as well as calcium oxalate stones while.
- The Hill’s® Prescription Diet® k/d® Early Support Feline Chicken, Vegetable & Rice Stew has is over 90% digestible and will provide 160% of essential amino acids that felines need.
- Its carbohydrates (nitrogen-free extracts), which are soluble carbs, are a little higher.
- It is more costly than other brands that serve the same purpose.
Guaranteed analysis (Dry matter basis)
If you are interested in Hill’s® Prescription Diet® k/d® Feline canned food, there are five types or varieties. Here is their guaranteed analysis on a dry matter basis.
P=Phosphorus and Na=Sodium
|Name||Protein (%)||Fats (%)||Carbs (%)||Fiber (%)||P (%)||Na (%)|
|Hill’s® Prescription Diet® k/d® Feline Chicken & Vegetable Stew||30.0%||26.6||38.0||2.8||0.49||0.23|
|Hill’s® Prescription Diet® k/d® Care Feline Vegetable & Tuna||30.0||24.8||37.4||2.8||0.49||0.24|
|Hill’s® Prescription Diet® k/d® Feline with Chicken||30.0||23.0||38.9||2.4||0.49||0.24|
|Hill’s® Prescription Diet® k/d® Feline with Tuna||29.0||22.1||41.7||1.5||0.45||0.24|
|Hill’s® Prescription Diet® k/d® Early Support Feline Chicken, Vegetable & Rice Stew||34.1||24.1||34.5||2.4||0.59||0.27|
Calories, cost, and feeding cost day on a basis of 8 lb.(3.6 kg) weighing cat
|Type||Cost/ 24 cans and calories||Daily feeding & cost|
|With Chicken||$52.99 (Chewy and Petco). Each 5.5 oz. can has 177 kcal||1.25 cans at a cost of $2.76|
|Chicken & Vegetable Stew||$39.99 (PetCareRx and Chewy). Each 2.9 oz. can has 70 kcal||3 cans going for $5.00|
|with Tuna||52.99 (PetCareRx and Chewy). Each 5.5 oz. can has 170 kcal||1 1/3 cans $2.94|
|Vegetable & Tuna Stew||39.99 (Chewy and PetCareRx). Each 2.9 oz. can has 77 kcal.||3 cans at a cost of $5.0|
|Early Support Feline Chicken, Vegetable & Rice Stew||$39.99 at Chewy. Each can is 2.9 oz. (82 g) and has 79 kcal||3 cans at a cost of $5.0|
2. Royal Canin Veterinary Diet Renal Support
Royal Canin has both wet and dry renal therapeutic diets with “a precise antioxidant complex, fatty acids from fish oil, low phosphorus, and targeted protein levels to help support kidney function,” as their Royal Canin notes.
All the wet foods will help stimulate appetite, are energy dense and very palatable. Therefore, your kitty doesn’t need much to meet his or her nutritional needs since cats with CKD tend to have poor appetites.
a). Canned or Wet Royal Renal Support (D E and T) wet cat food
If you want wet or canned renal support feline diet, you have a choice of going for the Renal Support D (delectable), E (enticing), or Renal Support T.
All foods are intended for intermittent or supplemental feeding only and have a maximum of 0.15% phosphorus and 2.0% crude fiber.
|Name||Crude protein (min)||Crude Protein (max)||Crude Fats (min)||Moisture (max)||Calories|
|Renal Support D Morsels in Gravy Canned Cat Food||6.5%||9.5%||4.5%||79.0%||1142 kcal ME/kg; 97 kcal ME/can|
|Renal Support E Loaf in Sauce Canned Cat Food||6.0%||9.0||5.1%||79.5%||Contains 1037 kcal ME/kg; 171 kcal ME/can|
|Renal Support T Slices in Gravy Canned Cat Food||5.1%||8.1%||4.5%||81.0%||962 kcal ME/kg; 82 kcal ME/can|
b). Royal Canin Renal Support A, F, Dry Feline Food
In these diets, A stands for aromatic, F flavorful and S savory.
Secondly, all these foods have a maximum of 8% moisture.
Finally, the Multifunction Renal Support + Hydrolyzed Protein Dry Cat Food supports both a sensitive stomach as well as kidneys.
|Name||Crude Protein (max)||Crude Protein (min)||Crude Fats||Crude Fiber||P (max)||Calories (calculated)|
|Renal Support A Dry Cat Food||21.0%||25.0%||15.0%||6.4||0.57%||3790 kcal ME/kg, 345 kcal ME/cup|
|Renal Support F Dry Cat Food||24.0%||28.0%||15.0%||5.8%||0.6%||3811 kcal ME/kg, 373 kcal ME/cup|
|Renal Support S Dry Cat Food||22.5%||26.5%||19.5%||5.0%||0.55||4061 kcal ME/kg, 398 kcal ME/cup|
|Multifunction Renal Support + Hydrolyzed Protein||23.0%||–||18.0%||5.6%||0.64%.||3979 kcal ME/kg, 402 kcal ME/cup|
3. Hill’s Prescription Diet k/d Feline Dry Cat Food
Like its wet counterpart, this complete and balanced dry feline diet is a work of veterinarians and nutritionists. It will support kidney function and ensure your feline pal doesn’t lose weight due to poor appetite that is common to kitties with CKD.
- It is low in sodium (0.26) and has controlled phosphorus (0.52) level
- Has essential amino acids, L-Carnitine, omega-3 fatty acids
- Will boost appetite, thanks to the Enhanced Appetite Trigger (EAT) Technology.
- Promotes high-calorie intake being high in calories
- Its S+OXSHIELDTM technology helps in preventing urinary stones (calcium oxalate and struvite.
- It supports heart and kidney function.
- Animal feeding testing following AAFCO protocol found the food complete and balanced for adult maintenance.
- It higher in carbohydrates as evidenced in its guaranteed analysis.
Guaranteed analysis based on dry matter.
Hill’s Prescription Diet k/d Feline Dry is available in three varieties.
|Product name||Protein (%)||Fats (%)||Carbs (%)||Fiber (%)||Phosphorus (%)||Sodium (%)|
|Early Support Feline with Chicken Dry Food||34.0||21.0||38.4||1.5||0.56||0.25|
|With Ocean Fish||29.8||23.1||40.6||40.6||40.6||40.6|
Cost, calories, feeding, and daily feeding cost for 8 lb. (3.6 kg) cat
|Type||Price/8.5 lb. bag ($) and calories||Feeding and cost|
|Feline with Chicken (4 and 8.5 lb.)||$52.99 (Chewy, PetFlow and calorific value of 4235 kcal/kg||1/2 cup (55 g) at a cost of $0.76|
|Feline with Ocean Fish (4 and 8.5 lb.).||$52.99 (Chewy, PetFlow, PetCareRx, and Petco) and has a calorific value of 4239 kcal/kg.||3/8 cup (50 g) at a cost of $0.68|
|Early Support Feline with Chicken Dry Food||$50.99 at Petco, PetCareRx and Chewy and has 4203 kcal/kg (536 kcal/cup)||3/8 cup (50 g) at a cost of $0.66|
4. Buffalo Blue Natural Veterinary Diet KM Kidney + Mobility support Dry
Kidney problems and mobility are two common problems in cats, especially as they age. Buffalo Blue Natural Veterinary Diet KM Kidney + Mobility support will support these two functions.
- It has restricted phosphorus levels of 0.4% and 0.7% minimums and maximums, while sodium doesn’t exceed 0.35% on dry matter basis.
- The manufacturer uses high-quality protein without poultry by-product meals.
- It’s grain-free, i.e., it doesn’t have corn, wheat, soy, artificial preservatives, or flavors.
- It is loaded with DHA, chondroitin, and glucosamine for mobility and healthy joints.
- It has omega-3 fatty acids, omega-6 fatty acids, L-Carnitine, and cranberry (good for urinary tract health).
- It has selected minerals and vitamins to boost immunity and maintain a proper oxidative balance that includes vitamins A, and C, potassium, and other antioxidants. Oxidative stress can worsen kidney damage.
- Its manufacturing process ensures it retains nutrient potency.
While it is a wonderful product that most felines will enjoy eating, it costs considering that a seven pounds goes for $42.99 at most of the leading vendors including Amazon.com, Petco, and Chewy.
Guaranteed analysis and calories
Crude protein (min): 26), crude fat (min): 18, crude fiber (ma) 6, moisture (max): 9.0 max while its calories stand at 3,934 Kcals/kg or 425 Kcals/cup.
Usual feeding is a ¼-1/2 cup for 5-9 lbs. cat and if 10 – 14 lbs. feeding is between 1/2 and 3/4 cup. A standard cup is about 8 oz.
5. Purina Pro Plan Veterinary Diets NF Kidney Function Formula Feline Food
Purina Pro Plan has both wet and dry early and advanced Veterinary Diets NF Kidney Function feline foods, intended to boost kidney function.
- Have a restricted amount of high-quality proteins
- Reduced phosphorus to prevent kidney overload
- Have omega-3 fatty acid, which is an essential source of DHA and EPA.
- Contain antioxidants to neutralize free radicals
- Its energy-dense formulation will ensure that your cat’s lean muscle does not waste away, especially the dry one.
- A few cat owners have noted that their kitties refused to eat this diet.
a). Purina Pro Plan Veterinary Diets NF Kidney Function Early and Advanced Care Feline Canned
If you want the wet formula, Purina Pro Plan Veterinary Diets NF Kidney Function has the Early and Advanced Care Feline canned.
|Purina Pro Plan Veterinary Diets NF Kidney Function Early Care Canned||Purina Pro Plan Veterinary Diets NF Kidney Function Advanced Care Canned|
|Crude Protein (min)||6.0%||6.5%|
|Crude Fats (min)||4.0%||3.0%|
|Crude Fiber (max)||3.0%||3.0%|
|Moisture content (max)||77.0%||77.0%|
|Calories||1059 kcal/kg, 165 kcal/can||1039 kcal/kg, 162 kcal/can|
|Feeding||Intermittent or supplemental||Intermittent or supplemental|
|Best prices (24, 5.5 Oz. cans )||51.99 at Chewy||51.99 at Chewy|
b). Purina Pro Plan Veterinary Diets NF Kidney Function Early and Advanced Care Feline Dry
The dry Veterinary Diets NF Kidney Function has the early and advanced care each in 3.15 and 8-pound packages.
|Purina Pro Plan Veterinary Diets NF Kidney Function Early Care Feline Dry Formula||Purina Pro Plan Veterinary Diets NF Kidney Function Advanced Feline Dry Formula|
|Crude Protein (min)||26.5%||33.0%|
|Crude Fats (min)||16.0%||13.0%|
|Crude Fiber (max)||5.0%||5.0%|
|Moisture content (max)||12.0%||12.0%|
|Calories||4085 kcal/kg or 536 kcal/cup||4041 kcal/kg or 494 kcal/cup|
|Feeding||Intermittent or supplemental||Intermittent or supplemental|
|Best prices (8 lbs.)||$45.99 Chewy||$45.99 chewy|
6. HI-TOR Veterinary Select Neo Diet Canned Cat Food for Kidney health
HI-TOR Veterinary Select Neo Diet Canned Cat Food is a vet recommended feline that has reduced amounts of phosphorus, sodium, and proteins for adult maintenance that supports kidney health.
- It is highly digestible and flavorful to encourage eating even by felines with low appetite.
- Doesn’t have any artificial flavors or colors
- It is low in ash levels.
- Costs lower when compared to other brands of the same caliber.
- Some buyers not that their felines eat only a very small amount of this food.
- Crude protein 8.00% min
- Crude fat 10.00% min
- Crude fiber 1.00% max
- Moisture 78.00% max
- Ash 1.90% max
- Phosphorus 0.10% max
A pack of 24 cans each weight 5.5 oz. goes for $21.99. Your feline weight 6-8 lbs. needs 1 can and finally, its calories are 1,316 kcal/kg.
7. Eukanuba Cat Veterinary Diet Renal Formula
If your kitty has kidney problems, both the wet and dry Eukanuba Cat Veterinary Diet Renal Formulas are an excellent choice.
- It’s palatable and has moderate in high quality, animal-sourced protein to boost kidney function.
- Has correct omega-3 and omega-6 fatty acid ratio, i.e., 5-10:1, making it suitable for lowering pressure and hypertension in the kidney. Also, omega-3 fatty acids that will promote kidney filtration process. All these benefits will slow the progression of CKD.
- Soy isolated protein ensures that the level of phosphorus is low.
- The added citrate helps maintain pH balance.
- The beet pulp, FOS, Gum Arabic serve as Nitrogen Trap Fibre System to help increase nitrogenous waste excretion via feces, consequently reducing the amount removed via kidneys.
|Nutrient/Ingredient||Feline Dry||Feline Canned|
|Feeding||50-70 g||170-235 g|
|£10.99 (at £7.33/kg) ( Pets at home)|
8. Dave’s Pet Food Restricted Diet Phosphorus Wet – New Formula
While the older formulation had a limited amount of protein, the new formula only has restricted phosphorus and sodium. Instead of reducing protein, they shifted to using high quality, highly digestive proteins.
- Its formulation supports renal function as it has a low sodium amount to ensure correct blood pressure balance and phosphorus to reduce the burden on kidneys in excreting the excess amounts.
- Uses chicken broth and chicken as their first ingredients
- Its grain-free making it the right choice if your feline has a sensitive stomach,
- It has added vitamins, omega-3 fatty acids (will improve coat quality), taurine, as well as other minerals and nutrients. All these added nutrients will improve your feline’s overall well being
|Guaranteed Analysis||As Fed||Dry Matter|
|Crude Protein (Min)||10.0%||12.58%||45.15%|
|Crude Fat (Min)||5.50%||6.15%||22.07%|
|Crude Fiber (Max)||4.0%||1.55%||5.56%|
|Phosphorus (Min/Max)||0.06 / 0.20%||0.11%||0.39%|
- As revealed from their guaranteed analysis, Dave’s Pet Food Restricted Diet Phosphorus feline diet is not low in proteins.
Prices: $36.90 per 24 cans each weighing 5.5 oz.at Chewy. Feed it as directed by your veterinarian.
Introduce new food gradually
Once you purchased a new low protein food, introduce it slowly over two weeks or as long as a month. Do this by reducing progressively on the old food as you increase the new one.
Don’t forget to continuous evaluation of your feline friend is necessary by your vet if your cats are on CKD therapeutic diets
Homemade low protein cat food recipes
If you rely on homemade diets, you will need the help of your veterinary to ensure these diets have lower levels of sodium and phosphorus. Also, fats, carbs, minerals, and vitamins, as well as taurine, must be present in homemade foods.
One option you have is going for egg whites which are low in phosphorus but have a higher amount of digestible proteins that will not strain your feline’s kidney.
Where to buy them
If you are looking for any of the above brands, try looking for them in your local pet stores. If you do not find them there, you have the option of buying them from leading online stores or the respective manufacturer’s websites for those that sell them online.
For instance, if you are in the UK, US or Australia, try looking at the local online stores first before going to the international ones to save on shipping cost.